The tragic loss of hundreds of lives in underground mine fires in West Virginia, Mexico, and China in late 2005 and 2006 revealed a serious deficiency in terms of emergency response. This is exemplified by the failure to rescue underground miners who survived the initial explosion. This failure resulted primarily because of an underestimation in the time required for rescue.
As recent mine fires dramatically demonstrate, the time needed to complete recovery operations into distant and/or remote mine positions typically is not measured in several hours but rather in several days. Extended time was and will be necessary to get rescue teams on the scene, diagnose the crisis, develop a safe plan of attack, and undertake the rescue.
To mine survivors, awaiting rescue is a life-threatening ordeal. Their most vital immediate need is finding breathable air, if possible. The multiple threats survivors must endure from toxic environments such as post-fire mine environments for up to several days are typically the following:
Exposure to elevated concentrations of carbon monoxide (CO);
Exposure to elevated concentrations of carbon dioxide, (CO2);
Exposure to reduced oxygen concentrations of (O2); and
Exposure to cold, ambient mine temperatures.
Fire poisons local mine air with CO and CO2 and consumes the O2 that is required to sustain life. Depending upon the elevated or reduced levels of these gases, the toxic mine air can cause death by asphyxiation either instantly (within minutes) or slowly (over days). The outcome of the last threat could be death by hypothermia.
Miners are trained to seek a habitable atmosphere in which to barricade and take refuge while awaiting rescue. Because finding breathable air that sustains life may be impossible, there is a technological need for the survivors to create a safe volume having habitable atmospheres with breathable air on demand.